How Much Do We Understand Ce L3 XANES? Ab Initio Insights into Configuration-Specific Screening at the Multiplet--Continuum Frontier
Abstract
How can local multiplet signatures, collective core-hole screening, and an extended photoelectron be reconciled in Ce L3 x-ray absorption near-edge spectra? Motivated by the question raised by Kvashnina [Chem. Eur. J. 30, e202400755 (2024)], we address this challenge using XSpectruplet, which couples local multiplet dynamics to continuum photoelectron propagation in self-consistent Kohn--Sham screening potentials. For Ce4+ in CeO2, our heuristic search identifies primary and secondary stationary screening states whose calculated white-line maxima lie about 7.3~eV apart after including their independently calculated total-energy difference, yet both retain the same effective local spectroscopic 4f0 sector. Their squared overlaps with the unrelaxed sudden reference give approximate statistical weights of 63\% and 30\%, respectively, within an independent-channel description. Their contrasting screening responses arise from collective rehybridization of occupied orbitals, rather than occupation of an additional localized 4f spectator, and produce contributions in both the main white-line and satellite regions. Ce3+ in monazite CePO4 provides the contrasting case of a localized 4f1 spectator participating explicitly in the multiplet dynamics. Independent relaxation of neutral 4f and white-line states gives a CeO2 pre-edge--white-line gap of 10.51~eV, close to the experimental separation of approximately 10.7~eV. Its excess over the fixed-background spectral gap defines a net correction, which we transfer heuristically to CePO4 without changing its local multiplet structure. This gives an estimated CePO4 gap of 6.38~eV, compared with approximately 8.1~eV experimentally. Distinct spectral contributions can thus arise from collective screening without a change in the effective local configuration.
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BibTeX
@misc{mirone2026much,
title = {{How Much Do We Understand Ce L3 XANES? Ab Initio Insights into Configuration-Specific Screening at the Multiplet--Continuum Frontier}},
author = {Alessandro Mirone},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.32968},
eprint = {2609.32968},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.32968},
}
RIS
TY - UNPB
TI - How Much Do We Understand Ce L3 XANES? Ab Initio Insights into Configuration-Specific Screening at the Multiplet--Continuum Frontier
AU - Alessandro Mirone
PY - 2026
DA - 2026/09/26
PB - arXiv
DO - 10.48550/arxiv.2609.32968
UR - https://arxiv.org/abs/2609.32968
AB - How can local multiplet signatures, collective core-hole screening, and an extended photoelectron be reconciled in Ce L_3 x-ray absorption near-edge spectra? Motivated by the question raised by Kvashnina [Chem. Eur. J. 30, e202400755 (2024)], we address this challenge using XSpectruplet, which couples local multiplet dynamics to continuum photoelectron propagation in self-consistent Kohn--Sham screening potentials. For Ce^4+ in CeO_2, our heuristic search identifies primary and secondary stationary screening states whose calculated white-line maxima lie about 7.3~eV apart after including their independently calculated total-energy difference, yet both retain the same effective local spectroscopic 4f^0 sector. Their squared overlaps with the unrelaxed sudden reference give approximate statistical weights of 63\% and 30\%, respectively, within an independent-channel description. Their contrasting screening responses arise from collective rehybridization of occupied orbitals, rather than occupation of an additional localized 4f spectator, and produce contributions in both the main white-line and satellite regions. Ce^3+ in monazite CePO_4 provides the contrasting case of a localized 4f^1 spectator participating explicitly in the multiplet dynamics. Independent relaxation of neutral 4f and white-line states gives a CeO_2 pre-edge--white-line gap of 10.51~eV, close to the experimental separation of approximately 10.7~eV. Its excess over the fixed-background spectral gap defines a net correction, which we transfer heuristically to CePO_4 without changing its local multiplet structure. This gives an estimated CePO_4 gap of 6.38~eV, compared with approximately 8.1~eV experimentally. Distinct spectral contributions can thus arise from collective screening without a change in the effective local configuration.
ER -